/*
 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.graal.hotspot.stubs;

import static com.oracle.graal.hotspot.HotSpotGraalRuntime.*;

import java.util.*;
import java.util.concurrent.*;

import com.oracle.graal.api.code.*;
import com.oracle.graal.api.meta.*;
import com.oracle.graal.compiler.*;
import com.oracle.graal.compiler.target.*;
import com.oracle.graal.debug.*;
import com.oracle.graal.debug.internal.*;
import com.oracle.graal.graph.*;
import com.oracle.graal.hotspot.*;
import com.oracle.graal.hotspot.bridge.CompilerToVM.CodeInstallResult;
import com.oracle.graal.hotspot.meta.*;
import com.oracle.graal.hotspot.nodes.*;
import com.oracle.graal.java.*;
import com.oracle.graal.nodes.*;
import com.oracle.graal.nodes.spi.*;
import com.oracle.graal.phases.*;
import com.oracle.graal.phases.PhasePlan.PhasePosition;

//JaCoCo Exclude

/**
 * Base class for implementing some low level code providing the out-of-line slow path for a snippet
 * and/or a callee saved call to a HotSpot C/C++ runtime function or even a another compiled Java
 * method.
 */
public abstract class Stub {

    /**
     * The linkage information for a call to this stub from compiled code.
     */
    protected final HotSpotForeignCallLinkage linkage;

    /**
     * The code installed for the stub.
     */
    protected InstalledCode code;

    /**
     * The registers destroyed by this stub.
     */
    private Set<Register> destroyedRegisters;

    public void initDestroyedRegisters(Set<Register> registers) {
        assert registers != null;
        assert destroyedRegisters == null || registers.equals(destroyedRegisters) : "cannot redefine";
        destroyedRegisters = registers;
    }

    /**
     * Gets the registers defined by this stub. These are the temporaries of this stub and must thus
     * be caller saved by a callers of this stub.
     */
    public Set<Register> getDestroyedRegisters() {
        assert destroyedRegisters != null : "not yet initialized";
        return destroyedRegisters;
    }

    /**
     * Determines if this stub preserves all registers apart from those it
     * {@linkplain #getDestroyedRegisters() destroys}.
     */
    public boolean preservesRegisters() {
        return true;
    }

    protected final HotSpotRuntime runtime;

    protected final Replacements replacements;

    /**
     * Creates a new stub.
     * 
     * @param linkage linkage details for a call to the stub
     */
    public Stub(HotSpotRuntime runtime, Replacements replacements, HotSpotForeignCallLinkage linkage) {
        this.linkage = linkage;
        this.runtime = runtime;
        this.replacements = replacements;
    }

    /**
     * Gets the linkage for a call to this stub from compiled code.
     */
    public HotSpotForeignCallLinkage getLinkage() {
        return linkage;
    }

    /**
     * Gets the graph that from which the code for this stub will be compiled.
     */
    protected abstract StructuredGraph getGraph();

    @Override
    public String toString() {
        return "Stub<" + linkage.getDescriptor() + ">";
    }

    /**
     * Gets the method the stub's code will be {@linkplain InstalledCode#getMethod() associated}
     * with once installed. This may be null.
     */
    protected abstract ResolvedJavaMethod getInstalledCodeOwner();

    /**
     * Gets a context object for the debug scope created when producing the code for this stub.
     */
    protected abstract Object debugScopeContext();

    /**
     * Gets the code for this stub, compiling it first if necessary.
     */
    public synchronized InstalledCode getCode(final Backend backend) {
        if (code == null) {
            Debug.sandbox("CompilingStub", new Object[]{runtime, debugScopeContext()}, DebugScope.getConfig(), new Runnable() {

                @Override
                public void run() {

                    final StructuredGraph graph = getGraph();
                    if (!(graph.start() instanceof StubStartNode)) {
                        StubStartNode newStart = graph.add(new StubStartNode(Stub.this));
                        newStart.setStateAfter(graph.start().stateAfter());
                        graph.replaceFixed(graph.start(), newStart);
                    }

                    PhasePlan phasePlan = new PhasePlan();
                    GraphBuilderPhase graphBuilderPhase = new GraphBuilderPhase(runtime, GraphBuilderConfiguration.getDefault(), OptimisticOptimizations.ALL);
                    phasePlan.addPhase(PhasePosition.AFTER_PARSING, graphBuilderPhase);
                    // The stub itself needs the incoming calling convention.
                    CallingConvention incomingCc = linkage.getIncomingCallingConvention();
                    final CompilationResult compResult = GraalCompiler.compileGraph(graph, incomingCc, getInstalledCodeOwner(), runtime, replacements, backend, runtime.getTarget(), null, phasePlan,
                                    OptimisticOptimizations.ALL, new SpeculationLog(), runtime.getDefaultSuites(), new CompilationResult());

                    assert destroyedRegisters != null;
                    code = Debug.scope("CodeInstall", new Callable<InstalledCode>() {

                        @Override
                        public InstalledCode call() {
                            Stub stub = Stub.this;
                            HotSpotRuntimeStub installedCode = new HotSpotRuntimeStub(stub);
                            HotSpotCompiledCode hsCompResult = new HotSpotCompiledRuntimeStub(stub, compResult);
                            CodeInstallResult result = graalRuntime().getCompilerToVM().installCode(hsCompResult, installedCode, null);
                            if (result != CodeInstallResult.OK) {
                                throw new GraalInternalError("Error installing stub %s: %s", Stub.this, result);
                            }
                            if (Debug.isDumpEnabled()) {
                                Debug.dump(new Object[]{compResult, installedCode}, "After code installation");
                            }
                            if (Debug.isLogEnabled()) {
                                Debug.log("%s", runtime.disassemble(installedCode));
                            }
                            return installedCode;
                        }
                    });

                }
            });
            assert code != null : "error installing stub " + this;
        }
        return code;
    }
}
